# Quod Erat Demonstrandum

## 2011/10/03

### 無題

Filed under: Additional / Applied Mathematics,HKCEE,NSS — johnmayhk @ 7:39 下午

Refer to the figure, the shaded region shown is bounded by the curves $y=\sin (2x)$ and $y=2\cos x$. Find the area of the shaded region.

$\int_{\pi/2}^{3\pi/2}(\sin(2x)-2\cos x)dx$

$-\int_{\pi/2}^{3\pi/2}2\cos xdx$.

Find $\frac{d}{dx}(\frac{-1}{x})$ from first principles.

1. Wanna be the tangent to touch the curve?

2. Tan lines

（完）